Article 17- Escalator Supporting Structure (Truss)The escalator Supporting Structure, called “Truss”, is the main chassis where all the machineries are installed on. The truss is composed of three main section (Upper, Middle, Lower) and normally the upper and lower sections are fixed and to provide variable height, the middle section can be altered.
There are two truss support angles at the top and bottom of the escalator which are placed on the main construction beams of the building and are not fixed (not welded, not screwed down, etc.) and are only held down by their own weight.
The truss material is from different steel alloys and shapes (Tube, Angle, and Channel) and combinations thereof in different sizes. A steel sheet is installed on the underside of the truss, which is called “Soffit”.
For the truss coating, paint is used for the indoor types and hot-dip galvanized for semi outdoor and fully outdoor.
The truss of the escalator must support a dead weight as well as structural rated load of 5000 N/m2 in compliance with EN 1993-1-1:2005 and the maximum deflection will be 1/750 of the horizontal distance between the construction beams. In the case the horizontal length of the truss being too long and causing more deflection than the authorized amount we have to use a middle support.
In order to assist with transportation of long escalators the truss can be divided into two or more sections and during installation they are assembled with special screws in coupling sections.